Shape memory polymer devices

ABSTRACT

Various shape memory polymer (SMP) devices are disclosed. Many of these SMP devices can be used as attachment and/or release mechanisms for any number of different applications. These SMP devices can use various characteristics of the SMP material to allow for various shape changes. These shape changes, in some embodiments, can be used to provide for release and/or attachment devices, for example, SMP bolts, SMP screws, SMP collars, SMP pillars, SMP panels, and/or SMP rivets, to name a few. An SMP device can include a first geometric state and a second geometric shape. The first geometric shape can restrict motion of two distinct objects relative to one another and the second geometrical shape can allow motion of two distinct objects relative to one another.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a non-provisional application that claims the benefit ofcommonly assigned U.S. Provisional Application No. 61/586,225, filedJan. 13, 2012, entitled “Shape Memory Polymer Devices,” and commonlyassigned U.S. Provisional Application No. 61/524,612, filed Aug. 17,2011, entitled “EMC Devices,” the entirety of which are hereinincorporated by reference for all purposes.

BACKGROUND

Shape memory polymer materials are not well known or used. And thesematerials have only received passing attention in industry. The uniquecharacteristics of these materials have yet to be exploited inmeaningful ways.

BRIEF SUMMARY

The terms “invention,” “the invention,” “this invention” and “thepresent invention” used in this patent are intended to refer broadly toall of the subject matter of this patent and the patent claims below.Statements containing these terms should not be understood to limit thesubject matter described herein or to limit the meaning or scope of thepatent claims below. Embodiments of the invention covered by this patentare defined by the claims below, not this summary. This summary is ahigh-level overview of various aspects of the invention and introducessome of the concepts that are further described in the DetailedDescription section below. This summary is not intended to identify keyor essential features of the claimed subject matter, nor is it intendedto be used in isolation to determine the scope of the claimed subjectmatter. The subject matter should be understood by reference to theentire specification of this patent, all drawings and each claim.

Generally, embodiments of the invention include SMP devices that includetwo different physical states. One state restricts motion between twodistinct objects, and the second state allows relative motion betweenthe two distinct objects. The SMP device can be or be part of one of thetwo distinct objects. The SMP device changes from one state to anotherstate when heated to temperatures near or above the glass transitiontemperature (T_(g)) of the SMP device and/or by application of anexternal force.

Embodiments of the invention include shape memory polymer (SMP) devicesin various configurations. These configurations can include retentiondevices, bolts, beams, support structures, rivets, screws, collars,retainers, etc. In one embodiment of the invention, an SMP device can beformed in a first shape, heated to temperatures near or above the glasstransition temperature of the SMP material, and formed into a secondshape. In this shape the SMP device can be used to secure two objectstogether. This can be done in a number of different ways. Later the SMPdevice can be heated again to temperatures near or above the glasstransition temperature. After being heated the SMP device can return tothe first shape either with or without an external force.

In another embodiment of the invention, an SMP structure (or device) canbe used in its original shape to offset an external force. The SMPstructure, for example, can be a beam, retention device, collar, orpillar, etc. The SMP structure can be heated to temperatures near orabove the glass transition temperature. When heated, the SMP structurecan change in response to the external force. For example, the SMPdevice may collapse, open, release, etc.

Various other embodiments of the invention are also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative embodiments of the present invention are described indetail below with reference to the following drawing figures:

FIGS. 1A, 1B, 1C, 1D, and 1E show an SMP bolt as fabricated, transformedunder temperature, in use, and removed after use according to someembodiments of the invention.

FIGS. 2A and 2B are flowcharts of methods for transforming and using theSMP bolt shown in FIG. 1 according to some embodiments of the invention.

FIGS. 3A, 3B, 3C, 3D, 3E, and 3F show an SMP bolt with tabs asfabricated, transformed under temperature, in use, and removed after useaccording to some embodiments of the invention.

FIGS. 4A and 4B are flowcharts of methods for transforming and using theSMP bolt with tabs shown in FIG. 3 according to some embodiments of theinvention.

FIGS. 5A, 5B, 5C and 5D show an SMP bolt as fabricated, transformedunder temperature, in use, and removed after use according to someembodiments of the invention.

FIG. 6 is a flowchart of a method for using the SMP bolt shown in FIG. 5according to some embodiments of the invention.

FIGS. 7A, 7B, 7C and 7D show an SMP collar as fabricated, transformedunder temperature, and in use with a shaft according to some embodimentsof the invention.

FIGS. 8A and 8B are flowcharts of methods for transforming and using theSMP collar shown in FIG. 7 according to some embodiments of theinvention.

FIGS. 9A, 9B, and 9C show an SMP collar as fabricated, transformed undertemperature, and in use with a shaft according to some embodiments ofthe invention.

FIGS. 10A and 10B are flowcharts of methods for transforming and usingthe SMP collar shown in FIG. 9 according to some embodiments of theinvention.

FIGS. 11A, 11B, 11C, and 11D show an SMP retainer as fabricated,transformed under temperature, and in use with a shaft according to someembodiments of the invention.

FIGS. 12A, 12B, 12C, and 12D show another SMP retainer as fabricated,transformed under temperature, and in use with a shaft according to someembodiments of the invention.

FIGS. 13A and 13B are flowcharts of methods for transforming and usingthe SMP retention devices shown in FIGS. 11 and 12 according to someembodiments of the invention.

FIGS. 14A, 14B, 15A, and 15B show an SMP column as fabricated and in useaccording to some embodiments of the invention.

FIGS. 16A, 16B, 17A, and 17B show another SMP column as fabricated andin use according to some embodiments of the invention.

FIGS. 18A, 18B, 19A, and 19B show another SMP column as fabricated andin use according to some embodiments of the invention.

FIGS. 20A, 20B, and 21 are flowcharts of methods for transforming andusing the SMP columns as shown in FIGS. 14, 15, 16, 17, 18, and 19according to some embodiments of the invention.

FIGS. 22A and 22B show an SMP wire according to some embodiments of theinvention.

FIGS. 23A, 23B, 24A, and 24B are flowcharts of methods for transformingand using the SMP wire as shown in FIG. 23 according to some embodimentsof the invention.

FIG. 25 shows a graph of the spring constant vs. temperature for SMPmaterial.

FIGS. 26A, 26B, and 26C show a collapsible SMP sandwich panel accordingto some embodiments of the invention.

FIGS. 27A and 27B are flowcharts of methods for transforming the SMPpanel shown in FIG. 25 into another shape according to some embodimentsof the invention.

FIGS. 28A and 28B show an SMP panel in a shaped and morphedconfiguration according to some embodiments of the invention.

FIGS. 29A and 29B are flowcharts for transforming the SMP panel shown inFIG. 28 into another shape according to some embodiments of theinvention.

FIGS. 30A, 30B, 30C and 30D show an SMP rivet as fabricated, transformedunder temperature, placed in use, and in use according to someembodiments of the invention.

FIGS. 31A and 31B are flowcharts of methods for transforming and usingthe SMP bolt shown in FIG. 30 according to some embodiments of theinvention.

FIGS. 32A, 32B, and 32C show an SMP rivet as fabricated, placed in use,and in use according to some embodiments of the invention.

FIGS. 33A and 33B are flowcharts of methods for transforming and usingthe SMP bolt shown in FIG. 32 according to some embodiments of theinvention.

FIGS. 34A, 34B and 34C show an SMP pin with a detent in an originalshape and two twisted configurations according to some embodiments ofthe invention.

FIGS. 35A and 35B are flowcharts of methods for creating and using theSMP pin shown in FIG. 34 according to some embodiments of the invention.

FIGS. 36A, 36B, and 36C show a socket that can be used with the SMP pinshown in FIG. 34 according to some embodiments of the invention.

FIGS. 37A, 37B, 37C, and 37D show the SMP pin in FIG. 34 interactingwith the socket shown in FIG. 36 according to some embodiments of theinvention.

FIGS. 38A, 38B and 38C show an SMP pin with a wedge detent in theoriginal shape and two twisted configurations according to someembodiments of the invention.

DETAILED DESCRIPTION

Illustrative embodiments of the present invention are described indetail below with reference to the following drawing figures.

Embodiments of the invention include shape memory polymer (SMP) devicesthat can be used in a number of configurations. Generally, embodimentsof the invention include SMP devices that include two different physicalstates. One state restricts motion between two distinct objects, and thesecond state allows relative motion between the two distinct objects.The SMP device can be or be part of one of the two distinct objects. TheSMP device changes from one state to another state when heated totemperatures near or above the glass transition temperature (T_(g)) ofthe SMP device and/or by application of an external force.

As another example, an SMP device can be fabricated in an originalshape. The SMP device can be heated to temperatures near or above theglass transition temperature of the SMP material and then changed into asecond shape; for example, with an external force. This external forcecan be any type of force; for example, a torsion force, a tensile force,a compression force, etc. The SMP device can then be placed in use inthe second shape. For example, in the second shape the SMP device can beused to secure two devices together, to support a load, to preventrelative motion, to allow relative motion, to twist a device, to be usedas an attachment mechanism, etc. The SMP device can then be heated totemperatures near or above the glass transition temperature and the SMPdevice can begin to change its shape back in the original shape. In somecases, an external force can be used to assist the SMP device inchanging its shape back to the original shape. Once in the originalshape or close thereto, in some cases, an action can occur; for example,two devices may no longer be secured together or a load may no longer besupported. Various embodiments of the invention incorporate thisexample.

As another example, an SMP device can be fabricated in an originalshape. While in the original shape, the SMP device can be used to resista load, provide support, attach two devices, etc. For example, in thesecond shape the SMP device can be used to resist a force or to supporta load. The SMP device can then be heated to temperatures near or abovethe glass transition temperature of the SMP material. At this point theSMP device is still in its original shape so it will not change backinto the original shape. But when heated to temperatures near or abovethe glass transition temperature and when either resisting a force orsupporting a load, the SMP device will change shape; for example, theSMP device will buckle, morph, open, etc. Various embodiments of theinvention incorporate this example.

Embodiments of the invention exploit the unique properties of SMPmaterials. One such property allows SMP materials to elicit shape memoryproperties. For instance, SMP materials can be formed in an originalstate. When they are heated to temperatures near or above the glasstransition temperature of the SMP material, the phase can change to arubber phase (or become pliable or shapeable) and the shape can bechanged into a second shape by applying an external force. Upon coolingto a temperature below the glass transition temperature, the shape ofthe SMP material will remain in the second shape. If the SMP material isheated again to temperatures near or above the glass transitiontemperature, the SMP material will naturally change back to the originalshape unless acted upon by an external load or force that restricts suchchanges. Typically, an SMP material can return to a shape that issubstantially similar to the original shape. As used herein, a shapethat is substantially similar to another shape has roughly the samegeneral shape although not perfectly similar.

But in some cases, an SMP material may not return completely to itsoriginal shape. That is, in some cases, a shape memory material may notreturn completely to its original shape after being heated totemperatures near or above the glass transition temperature. This effectmay be exacerbated by age, the number of times the SMP material isheated to temperatures near or above the glass transition temperature,mechanical distress, extreme environments, etc. Therefore, a shape issubstantially similar to another shape if the variation in shape variesless than 15% between the two.

SMP materials can include various thermoset, thermoplastic, or epoxypolymers. SMP materials may also include either a closed or open cellfoam material. SMP materials may include a polymer foam with a glasstransition temperature lower than the survival temperature of thematerial. For example, SMP materials may comprise TEMBO® shape memorypolymers, TEMBO® foams or Elastic Memory Composites, which consist of acomposite between reinforcing materials and TEMBO® shape memorypolymers, or combinations of the above.

The glass transition temperature of a given SMP material can be modifiedby modifying the mixture of materials in the SMP material. In this way,SMP devices with specific glass transition temperatures can be createdfor specific applications.

One example of an SMP material that can be used in the variousembodiments of the invention is TEMBO® available from CompositeTechnology Development in Lafayette, Colo.

Generally speaking, the glass transition temperature, T_(g), is thereversible transition in materials from a hard (or non-pliable) stateinto a rubber-like state. The glass transition temperature is unique tospecific materials and can be unique to different types or species forSMP materials. Different operational definitions for the glasstransition temperature are in use in the art. Several of these areendorsed as accepted scientific standards. Many definitions arearbitrary and yield different numeric results. At best, the variousvalues of glass transition temperature for a given substance typicallyagree within a few Kelvins. Embodiments of the invention are applicableregardless of the definition of the glass transition temperature used.

There are a number of ways to heat a SMP material or device to atemperature near or above the glass transition temperature. For example,SMP materials can be heated with convective heating using, for example,hot air guns, an oven, etc. As another example, SMP materials can beheated with radiation from a light source that applies, for example, IRor UV light. As another example, SMP materials can be heated withresistive heating elements that are embedded or coupled with the SMPmaterial. Resistive heaters can include, for example, resistive wireheaters. As another example, SMP materials can be heated with Inductiveor RF heat sources. Any other type of heat source can also be used.

A number of examples of SMP devices are described below.

SMP Bolts

FIGS. 1A, 1B, 1C, 1D, and 1E show SMP bolt 105 as fabricated,transformed under temperature, in use, and removed after use accordingto some embodiments of the invention. FIG. 1A shows SMP Bolt 105 in theoriginal shape. SMP bolt 105 can be made partially or completely fromSMP material(s). This shape does not include threads or tabs. SMP bolt105 can be heated to temperatures near or above the glass transitiontemperature of the SMP material and transformed into a second shape withan external force; for example, a compressive force that compresses SMPBolt into the second shape. FIG. 1B shows SMP bolt 105 having thissecond shape after cooling below the glass transition temperature. Thisshape can include a plurality of threads 112.

In use, SMP bolt 105 can be threaded into threaded socket 120 withinstructure 115 as shown in FIG. 1C. Structure 115, for example, can be anut. As another example, structure 115 can include two or morestructures that require SMP bolt 105 to secure or fasten the structurestogether. FIG. 1D shows SMP bolt 105 secured within threaded socket 120.SMP bolt 105 can be threaded into threaded socket 120 using standardtechniques. SMP bolt 105 can then be used in this state for any periodof time.

FIG. 1E shows SMP bolt 105 after SMP bolt 105 has been heated totemperatures near or above the glass transition temperature of the SMPmaterial. SMP bolt 105 can also be subject to external force 125, whichacts to pull SMP bolt 105 from threaded socket 120. In some embodiments,external force 125 can be applied at the same time as SMP bolt 105 issubject to temperatures near or above the glass transition temperature.The combination of heating SMP bolt 105 to temperatures near or abovethe glass transition temperature of the SMP materials, applying externalforce 125, and SMP bolt 105's mechanical contact with threads in socket120 can force SMP bolt 105 back to the original shape or to a shapesubstantially close to the original shape shown in FIG. 1A.

External force 125 can include a tool that is not integral with SMP bolt105. This tool can apply a compression force or tensile force to SMPbolt 105. For example, external force 125 can be applied by a hand tool,by hand, with a vibration table, etc. In some cases external force 125can be applied by a separate elastic element within the system. Aseparate elastic element may or may not be directly coupled to the SMPdevice. It can be permanent within the overall system. For example, anelastic element could be an extensional spring located next to an SMPdevice. A hybrid structure can include an SMP structure and an elasticelement (like a spring) that are combined in the same device.

In other embodiments, external force 125 can be applied after SMP bolt105 is subject to temperatures near or above the glass transitiontemperature. In such embodiments, SMP bolt 105 can transition to theoriginal shape or a shape substantially close to the original shape(e.g., as shown in FIG. 1A) under temperatures near or above the glasstransition temperature without aide of external force 125. Once SMP bolt105 has transitioned to the original shape, external force 125 can beapplied to extract SMP bolt 105 from threaded socket 120.

FIGS. 2A and 2B are flowcharts of processes 200 and 250 for transformingand using the SMP bolt shown in FIG. 1 according to some embodiments ofthe invention. Process 200 starts at block 205. At block 210 an SMP bolt(e.g., SMP bolt 105 shown in FIG. 1A) is formed in its original statewithout threads. At block 215 the SMP bolt is heated to temperaturesnear or above the glass transition temperature of the SMP material. Atblock 220 threads are transformed into the SMP bolt using any techniqueknown in the art, such as, extrusion, transforming, etc. At block 225the SMP bolt is cooled to a temperature below the glass transitiontemperature of the SMP material. At block 230 process 200 ends. Afterthe SMP bolt is fabricated as described in process 200, the SMP bolt canbe used for any fastening application.

Process 250 begins at block 255. At block 260 an SMP bolt can bethreaded into any threaded socket and used in application at block 265.At some point it may be desirable to remove the SMP bolt. At block 270the SMP bolt can be heated to temperatures near or above the glasstransition temperature of the SMP material for a period of time. Thisperiod of time, for example, may need to be long enough to allow the SMPbolt to return to the original shape or a shape substantially near tothe original shape. At block 275 the SMP bolt can be removed under anexternal force. Blocks 270 and 275 can occur at the same time or atdifferent times. Process 250 ends at block 280.

A SMP bolt can be used, for example, in various applications where boltremoval is required after use. A plurality of SMP bolts can be used asfasteners in an apparatus, for example, to join two materials together.At some point it may be desirable to remove the two devices from beingjoined together. The apparatus can simply be heated to temperatures nearor above the glass transition temperature of the SMP material and thenSMP bolts 105 can be removed. This can be done, for example, by placingthe apparatus in an oven for a period of time sufficient for SMP bolts105 to return to the original shape. After or at the same time as theheating, for example, the apparatus can be vibrated to remove SMP bolts105.

In one application, SMP bolts can be used to secure various componentswithin an automobile, such as securing door panels, dashboards, fabrics,etc. to the metallic frame. SMP bolts 105 would be ideal for suchapplications because of their low weight. At some point when theautomobile is being recycled, for example, the automobile can be placedin a large oven, heated to temperatures near or above the glasstransition temperature, and vibrated to release the various componentssecured to the metallic frame.

FIGS. 3A, 3B, 3C, 3D, 3E, and 3F show SMP bolt 305 with tabs 310 asfabricated, transformed under temperature, in use, and removed after useaccording to some embodiments of the invention. SMP bolt 305 can befabricated with tabs 310 as shown in FIG. 3A. SMP bolt 305 can befabricated from SMP material(s). SMP bolt 305 can then be heated totemperatures near or above the glass transition temperature of the SMPmaterial and formed into a second shape without tabs 310 as shown inFIG. 3B. This change from the original shape to the second shape canoccur under an external force and various processes can be used totransform

SMP bolt 305 into another shape. SMP bolt 305 can then be placed withintabbed socket 315 of apparatus 312 as shown in FIG. 3C. Once placedwithin apparatus 312, SMP bolt 305 can be heated to temperatures near orabove the glass transition temperature of the SMP material and SMP bolt305 can return to its original shape with a tab or tabs 310 as shown inFIG. 3D.

In some embodiments, SMP bolt 305 can return to its original shapewithout an external force. In other embodiments, SMP bolt 305 can returnto its original shape with an external force. For example, as shown inFIG. 3E SMP bolt 305 can include internal spring 320. Internal spring320 can provide a force that can aid in changing SMP bolt 305 from thesecond shape to the original shape. In order to change SMP bolt 305 fromthe original shape to the second shape (that is going from the shapeshown in FIG. 3A to the shape shown in FIG. 3B) a force greater than theforce applied by internal spring 320 must be applied. Internal spring320 can provide a large enough force to transform SMP bolt 305 intoanother state when within the rubber phase but not large enough totransform SMP bolt 305 when in the solid phase. Spring 320 can applyeither a compression or a tensile force to SMP bolt 305.

FIG. 3F shows SMP bolt 305 with internal channel 325. Internal channel325 can be used by a tool or other mechanical device to aid in forcingSMP bolt 305 to transition from the second shape to the original shape.For example, the tool may have a mandrel that can extend throughinternal channel 325 and engage bottom end 330 of SMP bolt 305. When SMPbolt 305 is heated to temperatures near or above the glass transitiontemperature of the SMP material, the mandrel extends through internalchannel 325 and engages with bottom 330 of SMP bolt 305. Once engagedthe tool can apply a force (e.g., compression or tensile force) on SMPbolt 305 to aid in transitions between the original shape and the secondshape. Various other tools and/or tooling devices can be used. Andvarious other modifications on SMP bolt 305 can be used to accommodateand/or assist with a tool that works with SMP bolt 305.

FIGS. 4A and 4B are flowcharts of processes 400 and 450 for transformingand using SMP bolt 305 with tabs shown in FIG. 3 according to someembodiments of the invention.

Process 400 starts at block 405. At block 410 an SMP bolt is formed inits original state with tab 310. At block 415 the SMP bolt is heated totemperatures near or above the glass transition temperature of the SMPmaterial. At block 420 tabs 310 are removed from the SMP bolt. Tab ortabs can be removed using any technique, such as extrusion,transforming, stretching, etc. At block 425 the SMP bolt is cooled to atemperature below the glass transition temperature of the SMP material.At block 430 process 400 ends.

After the SMP bolt is fabricated as described in process 400, the SMPbolt can be used for any fastening application. Process 450 begins atblock 455. At block 460 SMP bolt can be inserted into a tabbed socket.After insertion, the SMP bolt can be heated to temperatures near orabove the glass transition temperature of the SMP material at block 465and the SMP bolt can revert back to its original shape with tabs 310. Asnoted above, various tools or springs can be used to assist in restoringthe SMP bolt to the original shape. At this point the tabs can securethe SMP bolt within the tabbed socket by inner tabs. The SMP bolt canthen be cooled to a temperature below the glass transition temperatureof the SMP material at block 470 and the bolt can be used as needed atblock 475. Process 450 can then end at block 480.

FIGS. 5A, 5B, 5C and 5D show SMP bolt 505 as fabricated, transformedunder temperature, in use, and removed after use according to someembodiments of the invention. SMP bolt 505 can be transformed intoanother shape without tabs or threads as shown in FIG. 5A and can befabricated from SMP material. SMP bolt 505 can be fabricated with adiameter greater than the diameter of SMP bolt 510. As shown in FIG. 5B,threads can be added to SMP bolt 505 and/or the diameter of the bolt canbe narrowed. This can be done when the SMP bolt 505 is heated totemperatures near or above the glass transition temperature of the SMPmaterial. For example, threads 510 can be transformed into SMP bolt 505by extrusion, a mold, etc. In FIG. 5C, SMP bolt 505 can be threaded intoa corresponding nut, socket, or hole with the corresponding threads inapparatus 515. SMP bolt 505 can then be reheated to temperatures near orabove the glass transition temperature of the SMP material. SMP bolt 505can then try to return to its original shape. By returning to itsoriginal shape, SMP bolt 505 can be held more securely within apparatus515 as shown in FIG. 5D.

FIG. 6 is a flowchart of process 600 for using an SMP bolt like, forexample, the SMP bolt shown in FIG. 5 according to some embodiments ofthe invention. Process 600 begins at block 605. At block 610 an SMP boltis inserted into a threaded nut or bolt. At block 615 the SMP bolt isheated to temperatures near or above the glass transition temperature ofthe SMP material. As noted above, when heated to temperatures near orabove the glass transition temperature of the SMP material the SMP boltwill morph into its original shape or to a shape substantially similarto the original shape. At block 620 the SMP bolt can become tightlysecured within the threaded socket and/or nut. At block 625 process 600can end.

Various other SMP bolts with or without threads and/or with or withouttabs can be designed similar to the SMP bolts described above regardlessof dimensionality, composition, etc.

SMP Collars

FIGS. 7A, 7B, 7C and 7D show SMP collar 705 as fabricated, transformedunder temperature, and in use with a shaft according to some embodimentsof the invention. FIG. 7A shows SMP collar 705 fabricated in a circularshape. This circular shape can be the original shape of SMP collar 705.SMP collar 705 may or may not include gap 710, which can vary in size.SMP collar 705 can be made with any width, thickness and/or radius.

SMP collar 705 can be heated to temperatures near or above the glasstransition temperature of the SMP material and opened such that gap 710is much larger as shown in FIG. 7B. Gap 710 can be opened wide enough orwider in order to allow shaft 715 to slide within SMP collar 705 asshown in FIG. 7C. SMP collar 705 can then be heated to temperatures nearor above the glass transition temperature of the SMP material andreformed into the original shape around shaft 715 as shown in FIG. 7D.SMP collar 705 can be manually reformed into the original shape usingvarious types of tools or equipment. SMP collar 705 can also be reformedinto the original shape solely by the shape memory characteristics ofthe SMP material.

While SMP collar 705 is shown with a circular or c-shape, SMP collarscan have any shape. For example, SMP collars can be oval, square,rectangular, etc.

FIGS. 8A and 8B are flowcharts of process 800 and 850 for transformingand using an SMP collar such as the one shown in FIG. 7 according tosome embodiments of the invention. Process 800 starts at block 805. Atblock 810 the SMP collar is formed in an original shape, for example,that is circular or C-shape. The SMP collar can then be heated totemperatures near or above the glass transition temperature of the SMPmaterial at block 815. The SMP collar can then be opened at block 820.This opening can be done manually using any number of standard or customtools. At block 825 the SMP collar is cooled back to a temperature belowthe glass transition temperature (e.g., room temperature). The SMPcollar is then fixed in this open configuration. Process 800 can thenend at block 830.

FIG. 8B shows process 850 that starts at block 855. At block 860 the SMPcollar is slid into position around a shaft (e.g., shaft 715) at block860. At block 865 the SMP collar is heated to temperatures near or abovethe glass transition temperature of the SMP material at block 865. TheSMP collar can then return to its original shape at block 870. The SMPcollar can naturally return to the original shape or the SMP collar maybe forced to return to its original shape. At block 865, the SMP collaris cooled to a temperature below the glass transition temperature of theSMP material and SMP collar can return to its original shape. Process850 can end at block 880 with SMP collar secured around the shaft.

SMP collar 705 can be used in various assemblies. The shape memoryperformance of SMP collar 705 can securely fit around shaft 715 becauseSMP collar 705 shrinks after being subject to temperatures near or abovethe glass transition temperature. In some embodiments, the inner radiusof SMP collar 705 in the original shape can be smaller than the radiusof shaft 715. In this way, when raised to temperatures near or above theglass transition temperature of the SMP material, SMP collar 705 issnugly coupled around with shaft 715.

FIGS. 9A, 9B, and 9C show SMP collar as fabricated, transformed undertemperature, and in use with a shaft according to some embodiments ofthe invention. FIG. 9A shows SMP collar 905 fabricated in a straight ornearly straight configuration. SMP collar 905 can be heated totemperatures near or above the glass transition temperature of the SMPmaterial and molded around shaft 910 as shown in FIG. 9B. Thetemperature of SMP collar 905 can then be lowered to a temperature belowthe glass transition temperature and SMP collar 905 can perform itsfunction on shaft 910.

At some later point it may be desirable to remove SMP collar 905 fromshaft 910. SMP collar 905 can be heated to temperatures near or abovethe glass transition temperature, causing SMP collar to return to itsoriginal shape (i.e., the shape shown in FIG. 9A). This can be helpfulfor, among other things, releasing shaft 910 from SMP collar 905. Insome embodiments, a force can be applied on shaft 910. When SMP collar905 is heated, the combination of the heat and the force can cause SMPcollar 905 to open. Various other benefits can be realized.

FIGS. 10A and 10B are flowcharts of processes 1000 and 1050 fortransforming and using the SMP collar shown in FIG. 9 according to someembodiments of the invention. Process 1000 shown in FIG. 10A starts atblock 1005. At block 1010 an SMP collar (e.g., SMP collar 905) can beformed in the open configuration. For example, the SMP collar can beformed straight or nearly straight (e.g., see FIG. 9A). At block 1015the SMP collar is heated to temperatures near or above the glasstransition temperature of the SMP material and the SMP collar is formedaround a shaft at block 1020 (e.g., see FIG. 9B). At block 1025 the SMPcollar is cooled to a temperature below the glass transition temperatureof the SMP material while the SMP collar is secured around the shaft.Process 1000 can then end at block 1030.

Process 1050, shown in FIG. 10B, starts at block 1055. At block 1060 anSMP collar is in use while secured around a shaft (e.g., see FIG. 9B).The SMP collar can be in use for any period of time. At some pointremoval of the SMP collar may be desired. At block 1065 the SMP collarcan be heated to temperatures near or above the glass transitiontemperature of the SMP material. At some point during this heatingprocess the SMP collar may open because of its shape memory propertiesand/or the SMP collar is forced open by an outside force. Regardless,the shaft is removed from the SMP collar. At block 1030 process 1050 canend.

SMP Retention Devices

FIGS. 11A, 11B, 11C, and 11D show SMP retention device 1105 asfabricated, transformed under temperature, and in use with a shaftaccording to some embodiments of the invention. FIG. 11A shows SMPretention device 1105 as fabricated in its original shape. SMP retentiondevice can include pocket 1108. In FIG. 11B shaft 1110 is placed withinpocket 1108. While shaft 1110 is shown with ball 1112, any type of shaftwith an enlarged head may be used. Any shape may be used; for example, ashaft with a cube, cylinder, pyramid, cone, etc.

SMP retention device 1105 can then be heated to temperatures near orabove the glass transition temperature of the SMP material, after which,as shown in FIG. 11C, SMP retention device 1105 can be formed in aclosed configuration. In the closed configuration, ball 1112 is securedwithin SMP retention device 1105 by closing pocket 1108 around ball1112. In this way retention device 1105 can retain ball 1112 and shaft1110 in place. SMP retention device 1105 can then be cooled to atemperature below the glass transition temperature of the SMP materialof the SMP retention device 1105. FIG. 11D shows SMP retention device1105 after being heated to temperatures near or above the glasstransition temperature of the SMP material. When heated SMP retentiondevice 1105 may return to the original shape and shaft 1110 may bereleased. SMP retention device 1105 may return to its original shapewith or without the aide of an outside force. In some embodiments, aforce applied to shaft 1110 when SMP retention device 1105 is totemperatures near or above the glass transition temperature can aide inopening pocket 1108 and allowing ball 1112 to release.

FIGS. 12A, 12B, 12C, and 12D show a two-sided SMP retention device 1205as fabricated, transformed under temperature, and in use with a shaftaccording to some embodiments of the invention. FIG. 12A shows singleSMP retention device 1205 as fabricated in the release state. FIG. 12Bshows single SMP retention device 1205 in the retention state. Thestorage state can be created by heating SMP retention device 1205 andtransforming it from the release state to the retention state. FIG. 12Cshows two single SMP retention devices 1205 securing shaft 1110 betweenthe two SMP retention devices 1205. FIG. 12D shows the two SMP retentiondevices 1205 after being heated to temperatures near or above the glasstransition temperature of the SMP material. Both retention devices canreturn to the release state or close thereto. Force 1215 on shaft 1110can aid in opening the two SMP retention devices and partially forcingthem into the release state.

FIGS. 13A and 13B are flowcharts of processes 1300 and 1350 fortransforming and using the retention devices shown in FIGS. 11 and 12according to some embodiments of the invention. Process 1300 as shown inFIG. 13A begins at block 1305. At block 1310 a retention device isformed in the open configuration from SMP materials. Some type of jointcan be created within the SMP material in block 1315. This joint can beformed by joining two separate SMP materials or within a single SMPmaterial. At block 1320 the retention device is heated to temperaturesnear or above the glass transition temperature of the SMP material. Atblock 1325 the retention device is forced into the storage state. Theretention device can secure a ball shaft when in the storage state.

At block 1330 the SMP device is cooled to a temperature below the glasstransition temperature of the SMP material. In some embodiments, the SMPdevice can be coupled with an external force at block 1335. In block1340 process 1300 ends.

Process 1350 shown in FIG. 13B begins at block 1355. At block 1360 theretention device is heated to temperatures near or above the glasstransition temperature of the SMP material of the retention device. Atblock 1365 the joint is allowed to pull from the retention device underany influence from an external force. At block 1370 process 1350 ends.

SMP Columns

FIGS. 14A, 14B, 15A, and 15B show SMP column 1405 as fabricated and inuse according to some embodiments of the invention. FIG. 14A shows SMPcolumn 1405 fabricated in a buckled (or crooked, or bent) shape. FIG.14B shows SMP column 1405 in a straight shape. SMP column 1405 can befabricated in the buckled shape shown in FIG. 14A, heated totemperatures near or above the glass transition temperature of the SMPmaterial, and formed into a straight shape as shown in FIG. 14B.

FIG. 15A shows SMP column 1405 in use according to some embodiments ofthe invention. SMP column 1405 provides a resistive static force inopposition to the force provided by spring 1515. That is, spring 1515provides a force that pulls surface 1500 toward surface 1505. SMP column1405 provides an opposite, structural, and/or static force that can keepsurface 1500 at a height h₁ relative to surface 1505. While spring 1515is shown as providing a force in opposition to SMP column 1405, anyother type of force can be applied and/or any other type of mechanismcan apply a force. Spring 1515 can apply a compressive force on SMPcolumn 1405. SMP column 1405 resists any type of a force. FIG. 15B showsSMP column 1405 buckled after being heated to temperatures near or abovethe glass transition temperature of the SMP material. When heated, SMPcolumn 1405 returns to its original shape (e.g., the shape shown in FIG.14A), which is a buckled or crooked shape. Because of the buckling ofSMP column 1405, surface 1505 and 1500 are now separated by a height h₂that is less than h₁.

While SMP column 1405 is shown being fabricated in a buckled shape likethat shown in FIG. 14A, SMP column 1405 can be fabricated in a straightconfiguration like that shown in FIG. 14B. SMP column 1405 can still beused as a column as shown in FIG. 15A. When heated to temperatures nearor above the glass transition temperature of the SMP material, SMPcolumn 1405 can buckle from the force of spring 1515 without using therestorative action of the SMP material that comprises the column.

FIGS. 16A, 16B, 17A, and 17B show SMP column 1605 as fabricated and inuse according to some embodiments of the invention. SMP column 1605 asshown in FIG. 16A includes an elongated flat member comprised of SMPmaterial. SMP column 1605 can be much longer than it is wide or thick.SMP column 1605 can be heated to temperatures near or above the glasstransition temperature of the SMP material and curved along theelongated length of SMP column 1605 as shown in FIG. 16B. SMP column1605 can then be cooled to a temperature below the glass transitiontemperature of the SMP material. The curve along the elongated lengthcan provide an increased moment of inertia to SMP column 1605. Thisincreased moment of inertia may allow SMP column 1605 to support largerloads. SMP column 1605 can be coupled with structures 1705 and 1710 inany number of ways. In some cases, SMP column 1605 can be coupled withstructures 1705 and/or 1710 with a rigid, a flexible, and/or a rotatingattachment mechanism.

FIG. 17A shows SMP column 1605 supporting a load according to someembodiments of the invention. The curve along the elongated length ofSMP column 1605 allows SMP column 1605 to support larger loads than itwould without SMP column 1605.

SMP column 1605 can be heated to temperatures near or above the glasstransition temperature of the SMP material. At these temperatures theSMP material will return to the original shape shown in FIG. 16A.Portions or all of SMP column 1605 will then flatten out lowering themoment of inertia of SMP column 1605 and causing SMP column 1605 tobuckle under the applied load from spring 1705.

FIGS. 18A, 18B, 19A, and 19B show SMP column 1805 as fabricated and inuse according to some embodiments of the invention. SMP column 1805 caninclude a plurality of micro-buckling elements 1810 as shown in FIG.18A. In some embodiments, SMP column 1805 can be a hollow cylinder.Micro-buckling elements 1810 can be accordion shaped. SMP column 1805can be heated to a temperature near or above the glass transitiontemperature of the SMP material and elongated as shown in FIG. 1810.When elongated, micro-buckling elements 1810 can stretch out extendingthe length of SMP column 1805. Once SMP column 1805 has been stretchedto the appropriate length, SMP column 1805 can be cooled to atemperature below the glass transition temperature of the SMP material.

The cooled SMP column 1805 can then be used to support a load as shownin FIG. 19A. Force 1910 is applied between surface 1901 and 1902. Thesesurfaces are likewise supported by SMP column 1805, which resists force1910. Surfaces 1901 and 1902 can be kept a distance h₁ from each otherbecause of SMP column 1805. An alignment mechanism can be used to keepsurfaces 1901 and 1902 from shifting latterly. An alignment mechanismcan include complementary shafts that allow thinner shaft 1915 to slidewithin shaft 1920.

When SMP column 1850 is again heated to a temperature near or above theglass transition temperature of the SMP material, force 1910 can causethe micro-buckling elements to collapse or buckle, reducing the distancethe two surfaces 1901 and 1902 are from each other. Thus SMP column 1805can be used to provide a single direction actuator.

FIGS. 20A, 20B, and 21 are flowcharts process 2000, 2050 and 2100 fortransforming and using the SMP columns as shown in FIGS. 14, 15, 16, 17,18, and 19 according to some embodiments of the invention.

Process 2000 can begin at block 2005 in FIG. 20A. At block 2010 an SMPcolumn (e.g., SMP column 1405, 1605, and 1805) can be formed in thecollapsed configuration. The types and shapes of collapsedconfigurations can vary as shown above. At block 2015, the SMP columncan be heated to a temperature near or above the glass transitiontemperature of the SMP material. At block 2020, the SMP column can beforced into an elongated configuration. Various tools, jigs, and/orapparatus can be used to force the SMP column into the elongatedconfiguration.

At block 2025 the SMP column can be cooled to a temperature below theglass transition temperature of the SMP material. At block 2030 the SMPcolumn can be put to use. That is, for example, the SMP column devicecan be coupled to an apparatus to restrict a force. At block 2035,process 2000 can end.

Process 2055 can begin at block 2055 in FIG. 20B. At block 2060 the SMPcolumn is used to support a load. At block 2065 the SMP column is heatedto a temperature near or above the glass transition temperature of theSMP material. Once heated, the SMP column can collapse under force fromthe external load at block 2070. Process 2050 can end at block 2075.

Process 2100 can begin at block 2105. At block 2110 an SMP pillar can beused to support a load or an external force. At block 2115 the SMPdevice can be heated to a temperature near or above the glass transitiontemperature of the SMP material. Once heated to these temperatures, theSMP column can then deform and/or collapse in response to the appliedexternal force at block 2120. This deformation or collapse can occurfrom the applied external force and not from the internal shape memorycharacteristic of SMP materials.

SMP Wire

FIGS. 22A and 22B show SMP wire 2205 according to some embodiments ofthe invention. In FIG. 22A SMP wire 2205 is formed in a spring, coiled,or wound shape. In FIG. 22B SMP wire 2205 is in a straightened shape.SMP wire 2205 can be heated to a temperature near or above the glasstransition temperature of the SMP material in order to change the shapefrom the spring configuration to the straightened configuration.

FIGS. 23A, 23B, 24A, and 24B are flowcharts of process 2300, 2350, 2400,and 2450 for transforming and using the SMP wire as shown in FIG. 23according to some embodiments of the invention.

Process 2300 starts at block 2305 in FIG. 23A. An SMP wire is formed ina coiled, spring, or wound shape at block 2310. At block 2315, the SMPwire is heated to a temperature near or above the glass transitiontemperature of the SMP material. At block 2320, the SMP wire iselongated and/or stretched while heated to a temperature near or abovethe glass transition temperature of the SMP material, after which atblock 2325 the SMP wire can be cooled to a temperature below the glasstransition temperature of the SMP material. Process 2300 can end atblock 2330.

Process 2350 starts at block 2355 in FIG. 23B. The elongated SMP wire isprovided at block 2360. At block 2365 the SMP wire is heated to atemperature near or above the glass transition temperature of the SMPmaterial. When heated to such a temperature, SMP wire returns to itsoriginal coiled, spring, or wound shape. At block 2370 the SMP coil canbe cooled to a temperature below the glass transition temperature of theSMP material. Process 2350 can end at block 2375.

In FIG. 24A process 2400 starts at block 2405. At block 2410 anelongated SMP wire is formed from SMP material (e.g., like SMP wire 2205in 22B). At block 2415 the SMP wire is heated to a temperature near orabove the glass transition temperature of the SMP material. At block2420 the SMP wire is formed into a coiled configuration (e.g., like SMPwire 2205 in 22A). At block 2425 the SMP wire can be cooled to atemperature below the glass transition temperature of the SMP material.And process 2400 can end at block 2430. At some point, the SMP springmay need to elongated or change back to the original shape. This can bedone by heating the SMP back to a temperature above the glass transitiontemperature.

Process 2450 is shown in FIG. 24B and starts at block 2455. At block2460 the coiled SMP spring can be used in a mechanical application. ThisSMP spring can be an SMP spring formed using process 2400 or an SMPspring fabricated in a coiled configuration. At block 2465 the SMPspring is heated to adjust the spring constant of the material. FIG. 25is a graph that shows how spring constant changes with heat. Heat can beapplied using various electrical heaters coupled with the SMP spring.Returning to FIG. 24B, at block 2470 the SMP spring can be used with thedifferent spring constant. Process 2450 can end at block 2475. In suchembodiments the SMP spring can act as a variable spring constant spring.

FIG. 25 shows a spring constant curve temperature. As noted in thefigure, the spring constant of SMP materials varies inversely withtemperature over a range of temperatures. Thus, as the temperature ofthe SMP device varies, the spring constant will likewise vary.Typically, the spring constant of the SMP device will decrease as thetemperature increases. Thus, embodiments of the invention provide forsprings that have spring constants that vary with temperature.

SMP Panels

FIGS. 26A, 26B, and 26C show collapsible SMP sandwich panel 2600 in theoriginal, compressed, and original shapes, respectively, according tosome embodiments of the invention.

As shown in FIG. 26A, SMP sandwich panel 2600 includes face sheets 2601and 2602, and SMP layer 2605. Face sheets 2601 and 2602 can include anytype of material and can be rigid or flexible. In some embodiments, facesheets 2601 and 2602 can be constructed from thin metallic materials,fiber reinforced materials, composite materials, etc. Core 2605 caninclude SMP materials. FIG. 26A shows SMP sandwich panel 2600 in theoriginal configuration.

FIG. 26B shows SMP sandwich panel 2600 in a compressed configuration.Once heated to a temperature near or above the glass transitiontemperature of the SMP material, SMP sandwich panel 2600 can be forcedinto the compressed configuration by forcing face sheets 2601 and 2602together. In the compressed configuration, core 2605 of SMP sandwichpanel 2600 is compressed by this external force. SMP sandwich panel 2600can then be cooled to a temperature below the glass transitiontemperature of the SMP material and held in the compressedconfiguration.

SMP sandwich panel 2600 can be reheated to a temperature near or abovethe glass transition temperature of the SMP material. SMP sandwich panel2600 can then return to the original shape. An external force maycontribute to SMP sandwich panel 2600 transition from the compressed tothe original shape. SMP sandwich panel 2600 can be used in variousconfigurations or embodiments where the thickness of a material variesover time.

FIGS. 27A and 27B are flowcharts of processes 2700 and 2750 fortransforming the SMP panel shown in FIG. 25 to another shape accordingto some embodiments of the invention. Process 2700 begins at block 2705.At block 2710 the SMP sandwich panel (e.g., SMP sandwich panel 2600) canbe formed in the original state (see e.g., FIG. 26A). At block 2715 theSMP sandwich panel can be heated to a temperature near or above theglass transition temperature of the SMP material. At block 2720 the SMPsandwich panel can be compressed (see e.g., FIG. 26B). At block 2725,the SMP sandwich panel can be cooled to a temperature below glasstransition temperature. At block 2730, process 2700 can end.

Process 2750 in FIG. 27B begins at block 2755. At block 2760 the SMPsandwich panel can be used in any of various applications. At block 2765the SMP material (e.g., SMP core 2605) can be heated to a temperaturenear or above the glass transition temperature of the SMP material. Atblock 2770 the SMP panel can be allowed to return to the original shape.The fundamental nature of SMP materials allows the SMP sandwich panel tochange back to the original shape. In some embodiments, the SMP sandwichpanel can return to the original shape with the restorative behavior ofthe SMP core. In other embodiments, the SMP sandwich panel can return tounder an external force. At block 2775, process 2750 can end.

FIGS. 28A and 28B show SMP panel 2800 in a shaped and morphedconfiguration according to some embodiments of the invention. In FIG.28A, SMP panel 2800 includes face skin 2805 and SMP material 2810. TheSMP material can be similar to the SMP materials described elsewhere inthis disclosure. Likewise the face skin can be similar to the face skindescribed elsewhere in this disclosure. In some embodiments, face skin2805 and SMP material 2810 may have different coefficients of thermalexpansion. Because of this difference, as the two materials are heatedto a temperature near or above the glass transition temperature of theSMP material, the two materials will expand at different rates. Thisexpansion will cause SMP panel 2800 to bow or curve as shown in FIG.28B. If the temperature of the SMP material 2810 is lowered below theglass transition temperature, SMP material 2810 will maintain the curvedshape.

FIGS. 29A and 29B are flowcharts of processes 2900 and 2950 fortransforming an SMP panel (e.g., like the one shown in FIG. 28) intoanother shape according to some embodiments of the invention. The SMPpanel can include a face sheet and an SMP layer. Process 2900 in FIG.29A starts at block 2905. At block 2910 a two-layer sandwich panel isformed in the original shape (e.g., the shape shown in FIG. 28A). Atblock 2915 the SMP layer and/or the face sheet can be heated to atemperature near or above the glass transition temperature of the SMPmaterial. The panel can then naturally and/or under an external forcedeform into a curved or bowed shape at block 2920. At block 2925 the SMPmaterial and/or face sheet can be cooled to a temperature below theglass transition temperature of the SMP material. At this point the SMPpanel may retain its curved or bowed shape. Process 2900 can then end atblock 2930.

Process 2950, in FIG. 29B, begins at block 2955. At block 2960 an SMPpanel is used in its curved configuration (e.g., see FIG. 28B). The SMPpanel can be heated to a temperature near or above the glass transitiontemperature of the SMP material within the SMP panel at block 2965.After heating, the SMP panel can return to its original, non-curvedshape at block 2970. At block 2975, process 2950 can end.

FIGS. 28 and 29 show SMP panels formed in a straight shape and deformedinto a curved shape. SMP panels can also be formed in a curved shape,heated to a temperature near or above the glass transition temperatureof the SMP material, formed into a straight shape, cooled to atemperature below the glass transition temperature of the SMP material,and used in the straight shape. Later, the SMP panel can be heated to atemperature near or above the glass transition temperature of the SMPmaterial and SMP panel can return to the original shape naturally or byapplication of an external force.

SMP Rivets

FIGS. 30A, 30B, 30C and 30D show SMP rivets 3005 as fabricated,transformed under temperature, placed in use, and in use according tosome embodiments of the invention. FIG. 30A shows SMP rivet 3005 in itsoriginal shape. SMP rivet 3005, in its original shape, includes factoryhead 3015 and shop head 3020. SMP rivet 3005 can be constructed from anytype of SMP material. FIG. 30B shows SMP rivet 3005 in its deformedshape. In the deformed shape, SMP rivet 3005 includes only factory head3015. Shop head 3020 is completely removed. SMP rivet 3005 can betransformed into the deformed shape after being heated to a temperaturenear or above the glass transition temperature of the SMP material. Uponcooling, SMP rivet 3005 can remain in the deformed state.

In use, SMP rivet 3005, in its deformed state, can be used to secure orattach to materials together. For example, SMP rivet 3005 can be used tosecure sheets 3010 and 3011 together as shown in FIG. 30C. While onlytwo sheets are shown, any number of materials can be used. While twosheets are shown, SMP rivet 3005 can be used to secure any types ofmaterials together. SMP rivet 3005 can be inserted into aligned holeswithin 3010 and 3011. The width of the two materials combined can haveabout the same dimension as SMP rivet 3005 between factory head 3015 andshop head 3020. Once placed within the threaded socket, SMP rivet 3005can be heated to a temperature near or above the glass transitiontemperature of the SMP material. SMP rivet 3005 can then transition toits original shape with or without application of an external force.This force, for example, can be a tensile or compressive force. In theoriginal shape, the SMP rivet includes factory head 3015. The two sheets3010 and 3011 can be secured together between shop head 3020 and factoryhead 3015. SMP rivet 3005 can support tension loads (loads parallel tothe axis of SMP rivet 3005) and shear loads (loads perpendicular to theaxis of SMP rivet 3005).

FIGS. 31A and 31B are flowcharts of process 3100 and 3150 fortransforming and using an SMP rivet according to some embodiments of theinvention. Process 3100, shown in FIG. 31A, begins at block 3105. Atblock 3110, an SMP rivet is formed in its original shape with a shophead and a factory head (e.g., see FIG. 31A). At block 3115 the SMPrivet is heated to a temperature near or above the glass transitiontemperature of the SMP material. At block 3120 the SMP rivet is deformed(or transformed) into an elongated shape without the shop head. At block3125 the SMP rivet is cooled to a temperature below the glass transitiontemperature of the SMP material. Process 3100 can end at block 3130.

Process 3150, shown in FIG. 31B, begins at block 3155. At block 3160, anelongated SMP rivet, without a shop head, is inserted into a threadedsocket. This threaded socket, for example, can be a hole within two ormore materials that are to be riveted together. At block 3165, the SMPrivet can be heated to a temperature near or above the glass transitiontemperature of the SMP material. At block 3170 SMP rivet can return tothe original shape with the shop head. This can be done by the naturalrestorative nature of the SMP material and/or aided by an outside force.Regardless of the mechanism, a shop head is formed, and the SMP rivet issnugly affixed within the hole. Process 3150 can end at block 3175.

FIGS. 32A, 32B, and 32C show SMP rivet 3200 as fabricated, placed inuse, and in use according to some embodiments of the invention. FIG. 32Ashows SMP rivet 3200 in its original as fabricated shape. SMP rivet 3200can be constructed from any type of SMP material. SMP rivet can includeshaft 3205 and factory head 3210.

FIG. 32B shows SMP rivet 3200 inserted into a hole formed within twosheets 3215 and 3216. While only two sheets are shown, any number ofsheets can be used. And while sheets are shown, SMP rivet 3200 can beused to secure any types of materials together. After SMP rivet 3200 hasbeen inserted into the hole, SMP rivet 3200 can be heated to atemperature near or above the glass transition temperature of the SMPmaterial and deformed as shown in FIG. 32C. In some embodiments, thisdeformation may produce shop head 3220 on SMP rivet 3200. Thisdeformation requires an external force to reshape SMP rivet 3200.Specialty tools may be used and/or a blunt instrument can strike theshop head end of SMP rivet 3200 deforming SMP rivet 3200 as shown. Insome embodiments, this deformation may cause the diameter of shaft 3205to expand, filling in any unused space within the hole. SMP rivet 3200after deformation can secure sheets 3215 and 3216 together.

FIGS. 33A and 33B are flowcharts of process 3300 and 3350 fortransforming and using the SMP rivet shown in FIG. 32 according to someembodiments of the invention. Process 3300 begins at block 3305 in FIG.33A. At block 3310, an SMP rivet (e.g., SMP rivet 3200) is formed in itsoriginal shape without a shop head and with a factory head (e.g., seeFIG. 32A). At block 3315 the SMP rivet is placed within a hole. Thishole can include holes from multiple sheets, materials, panels, and/orapparatuses. At block 3320 the SMP rivet is deformed to include a shophead. Process 3300 can end at block 3325.

FIG. 33B shows process 3350, which begins at block 3355. At block 3360SMP rivet (e.g., SMP rivet 3200) is heated to a temperature near orabove the glass transition temperature of the SMP material. The SMPrivet could have been previously inserted into a hole and deformed toinclude a shop head (e.g., as shown in FIG. 32C). The SMP rivet is thenallowed to return to its original shape at block 3365. In someembodiments, an outside force can be used to help the SMP rivet returnto its original shape. For example, the SMP rivet and/or the materialwithin which it is attached can be mechanically or acoustically vibratedwhile at a temperature above the glass transition temperature of the SMPmaterial. Other external forces may be used. The heat, possibly incombination with an external force, can allow the SMP rivet to beremoved as shown in block 3370. At block 3375 process 3350 can end.

SMP rivet 3200 and/or process 3300 and 3350 can be used in variousmanufacturing processes such as automobile manufacturing. In someembodiments, SMP rivet 3200 can be used to secure a fixture to the frameof an automobile. For example, SMP rivet 3200 can be used to secure adoor panel (e.g., sheet 3216 in FIGS. 32A, 32B, and 32C) to a doorframe(e.g., sheet 3215 in FIGS. 32A, 32B and 32C). Process 3300 can be usedto secure SMP rivet 3200. Process 3350 can be used to remove SMP rivet3200 and, for example, ultimately remove the door panel from thedoorframe. The removal process can occur at a junkyard and/or at anautomobile recycling center.

SMP Pins

FIG. 34A show SMP pin 3400 with detent 3405 in an original shapeaccording to some embodiments of the invention. SMP pin 3400 is acylindrical member made at least partially from SMP materials. FIGS. 34Band 34C show SMP pin 3400 twisted along the longitudinal length of SMPpin 3400. When twisted, the bottom portion of SMP pin 3400 and detent3405 are twisted relative to the upper portion of SMP pin 3400. SMP pin3400 can be twisted from the original shape shown in FIG. 34 to a secondshape (e.g., either of the shapes shown in FIG. 34B or 34C), when heatedto a temperature near or above the glass transition temperature of theSMP material. An external force can be applied to transform the pin fromthe original shape to the second shape. This force, for example, can bea torsion force applied by an external tool or tools. After twisting,SMP pin 3400 can be cooled to a temperature below the glass transitiontemperature of the SMP material. SMP pin 3400 will then maintain thesecond shape.

SMP pin 3400 will return to the original shape or a shape close thereto,when reheated to a temperature near or above the glass transitiontemperature. In some situations, SMP pin 3400 may be maintained at atemperature near or above the glass transition temperature for a periodof time sufficient to allow the SMP to recover and allow the pin toreturn to or close to the pin's original shape. While SMP pin 3400 isshown twisted about 90 degrees, SMP pin 3400 can be twisted any degree.For example, SMP pin 3400 can be twisted 45, 90, 135, 180, 235, 270,315, or 360 or more degrees. The length of the SMP pin and/or the typeof SMP material used may limit the degree of twisting.

SMP pin 3400 may be completely or partially comprised of SMP material.For example, the ends of SMP pin 3400 may be comprised of a materialother than SMP material. A central pin may also be used that is or isnot comprised of SMP material that limits twisting to twisting along thelongitudinal length of SMP pin 3400. Moreover, detent 3405 can becomprised of any type of material.

FIG. 35A shows flow chart of process 3500 for creating an SMP pin.Process 3500 starts at block 3505. At block 3510 the SMP pin can beformed with a detent. The SMP pin can be formed from any manufacturingprocess that can produce a pin with a detent. SMP pin can be formed atleast partially from SMP material and/or can be formed in asubstantially cylindrical shape. In some configurations, the ends of thepin can be manufactured from non-SMP material.

At block 3515, the SMP pin can be heated to a temperature near or abovethe glass transition temperature of the SMP material. Once heated, thepin can be twisted such that the detent is twisted relative to otherportions of the pin at block 3520. The pin can then be cooled below theglass transition temperature at block 3525 while being held within thetwisted configuration. At block 3530, process 3500 can end.

Process 3550, shown in FIG. 35B, shows a flowchart for using the SMP pinaccording to some embodiments of the invention. Process 3550 begins atblock 3555. At block 3560 SMP pin 3400 can be inserted into socket 3610(shown in FIGS. 36A, 36B and 36C) that allows for passage of the pin andthe detent. FIG. 36A shows a top view, FIG. 36B shows a side view, andFIG. 36C shows an end view of socket 3610 and the channels. In someconfigurations, socket 3610 can have a diameter larger than the diameterof the pin without the detent, longitudinal channel 3620 that can allowpassage of the detent, and transverse channel 3630.

FIGS. 37A and 37B show a side view and an end view of SMP pin 3400 beinginserted into socket 3610. Longitudinal channel 3620 provides anadditional channel for detent 3405 to pass through socket 3610. At block3575 SMP pin is cooled to a temperature below the glass transitiontemperature.

Returning to FIG. 35B, at block 3565 SMP pin 3410 can be heated to atemperature near or above the glass transition temperature. At block3570, SMP pin 3410 can be allowed to twist back to the original shapecausing the detent to interfere with transverse channel 3630. An exampleof this is shown schematically in FIGS. 37C and 37D. FIGS. 37C and 37Dshow side and top views of detent 3405 twisted within socket 3610 suchthat detent 3405 mechanically interferes with the top of transversechannel 3630 restricting pin 3410 from being extracted from socket 3610.In this example detent 3405 rotates approximately 90 degrees. However,any rotation may be sufficient so long as the rotation rotates the pinfrom a position that is free to a position that locks the pin.

Referring back to FIG. 35B, process 3550 may end at block 3580.

In other embodiments of the invention, SMP pin 3800 can have detent 3805that is angled toward the bottom of the SMP pin in a wedge shape asshown in FIGS. 38A, 38B and 38C. Both SMP pin 3800 and/or detent 3805can be similar to SMP pin 3400 and/or detent 3405. SMP pin 3800 can beinserted into socket 3600 in a twisted configuration. In thisembodiment, detent 3805 does not slide into socket 3610 through channel3620. Instead, detent 3805 is jammed into the socket until the topsurface of detent 3805 engages with transverse channel 3630. In thisembodiment, SMP pin 3800 can be removed by heating SMP pin 3800 abovethe glass transition temperature. Above this temperature, SMP pin 3800will twist and detent 3805 can line up with channel 3620 allowing SMPpin 3800 to be removed under an external force.

In some embodiments, SMP pin 3400 and/or SMP pin 3800 can be taperedalong the longitudinal length of the pin. The end nearest the detent,for example, can have a smaller diameter than the other end.

Embodiments of the invention often use external forces to modify theshape of an SMP device. An external force can be applied by hand or by ahand tool that is not integral with the SMP device and/or system. Anexternal force can also be provided by an elastic member or force withinthe system. And an external force can be applied with an embeddedelastic element such as the one shown in FIG. 3E.

Embodiments of the invention also require heating of an SMP device. Heatcan be applied using convective heating (in an oven, hot air gun, etc.),radiation (i.e. UV lamps), inductive heating, RF heating, IR heating,resistive heating (embedded or surface mounted resistive wire heater),etc. This could also involve modifying the SMP with conductive fillers,fibers, etc. so that a voltage can be applied to the device itself forresistive heating. In the case of a device that contains a metalliccomponent (like a spring), the spring may also be used as a resistiveheating element.

Different arrangements of the components depicted in the drawings ordescribed above, as well as components and steps not shown or describedare possible. Similarly, some features and subcombinations are usefuland may be employed without reference to other features andsubcombinations. Features, components, benefits, methods, or processesdescribed in conjunction with one embodiment can be applied to any otherembodiment. Embodiments of the invention have been described forillustrative and not restrictive purposes, and alternative embodimentswill become apparent to readers of this patent. Accordingly, the presentinvention is not limited to the embodiments described above or depictedin the drawings, and various embodiments and modifications can be madewithout departing from the scope of the claims below.

1. A shape memory polymer device comprising: a body comprising a shapememory material having a first state and a second state, wherein in thefirst state the body is coupled with two objects and restricts themotion of the two objects relative to one another, wherein in the secondstate the body allows motion of the two distinct objects relative to oneanother, and wherein the body in the first state has a shape distinctfrom the shape of the body in the second state.
 2. The shape memorypolymer device according to claim 1, wherein in the first state the bodyis coupled with two or more objects and wherein in the second state thebody allows motion of at least two distinct objects relative to oneanother.
 3. The shape memory polymer device according to claim 1,wherein the shape memory polymer device transitions from the first stateto the second state when either the shape memory device is heated to atemperature near or above the glass transition temperature of the shapememory material and a force is applied on the shape memory device. 4.The shape memory polymer device according to claim 3, wherein the forceis an external force.
 5. The shape memory polymer device according toclaim 3, wherein the force is an external force that is applied using atool.
 6. The shape memory polymer device according to claim 1, furthercomprising a resistive heat element coupled with the body.
 7. The shapememory polymer device according to claim 1, further comprising amechanism coupled with the body that applies a force on the body thatforces the body to transition from the first state to the second state,and wherein the force is not sufficient to transition the body from thefirst state to the second state unless the body is heated to atemperature near or above the glass transition temperature of the shapememory material.
 8. The shape memory polymer device according to claim7, wherein the mechanism comprises a spring.
 9. The shape memory polymerdevice according to claim 8, wherein the spring comprises a resistiveheating element.
 10. The shape memory polymer device according to claim7, wherein the mechanism is coupled directly with the body.
 11. Theshape memory polymer device according to claim 1, wherein the shapememory polymer transitions to the second state through release of storedstrain energy in the shape memory polymer material.
 12. The shape memorypolymer device according to claim 1, wherein in the first state the bodycarries a load between the two objects.
 13. The shape memory polymerdevice according to claim 12, wherein in the second state a portion ofthe body collapses under the load when heated to a temperature above theglass transition temperature.
 14. The shape memory polymer deviceaccording to claim 1, wherein the relative motion between the twoobjects is inhibited by mechanical interference of a body.
 15. The shapememory polymer device according to claim 14, wherein the mechanicalinterference comprises at least one of a tab, a thread, or a factoryhead.
 16. The shape memory polymer device according to claim 1, whereinthe body transitions from the first state to the second state byreleasing stored energy in the shape memory material when heated to atemperature at or near a glass transition temperature of the shapememory material.
 17. A method comprising: providing a shape memorydevice in a system with two distinct objects, wherein the shape memorydevice is in a first state and the shape memory device comprises a shapememory material; and coupling the two distinct objects by transformingthe shape memory device from the first state into a second state. 18.The method according to claim 17, wherein the transforming includeseither or both of heating the shape memory device to a temperature nearor above the glass transition temperature of the shape memory materialand applying a force on the shape memory device.
 19. A methodcomprising: coupling two distinct objects using a shape memory devicethat is in a first state, wherein the shape memory device comprises ashape memory material; and transforming the shape memory device from thefirst state into a second state, wherein in the second state the twodistinct objects are decoupled.
 20. The method according to claim 19,wherein the transforming comprises either or both of heating the shapememory device to a temperature near or above the glass transitiontemperature of the shape memory material and applying a force on theshape memory device.
 21. A method for using a shape memory polymerattachment mechanism, the method comprising: fabricating a shape memorypolymer attachment mechanism in an original shape, wherein the shapememory polymer attachment mechanism includes shape memory polymermaterial; heating the shape memory polymer attachment mechanism to atemperature near or above the glass transition temperature of the shapememory polymer materials; transitioning the shape memory polymerattachment mechanism into a second shape while heated to a temperaturenear or above the glass transition temperature of the shape memorypolymer material; and placing the shape memory polymer attachmentmechanism in position for an application.